This thing will blow your mind. While the humans have been looking for immortality in every period of history, it appears that there is one species of jellyfish that are actually immortal. Turritopsis nutricula, known as immortal jellyfish, has the ability to transform its cells from mature state back to immaturity, in other words – back to youth. The immortal jellyfish leads a regular cycle of life, but after maturing and mating, it reverts back to its initial state. This ability to reverse the life cycle (in response to adverse conditions) is probably unique in the animal kingdom, and allows the jellyfish to bypass death

The bell-shaped immortal jellyfish measures up to a maximum of bout 4.5 millimeters (0.18 in) and is about the same in its length and width. Originating in the Caribbean, it has now spread worldwide. Some scientists claim that their mystery is soon to be solved and applied to humans, while others only expect it to improve the quality of life at our final stages. In spite of this remarkable ability, most of them are likely to fall victim to the general hazards of life as plankton, including being eaten by other animals, or succumbing to disease.